[SPARK-13823][CORE][STREAMING][SQL] Always specify Charset in String <-> byte[] conversions (and remaining Coverity items)

## What changes were proposed in this pull request?

- Fixes calls to `new String(byte[])` or `String.getBytes()` that rely on platform default encoding, to use UTF-8
- Same for `InputStreamReader` and `OutputStreamWriter` constructors
- Standardizes on UTF-8 everywhere
- Standardizes specifying the encoding with `StandardCharsets.UTF-8`, not the Guava constant or "UTF-8" (which means handling `UnuspportedEncodingException`)
- (also addresses the other remaining Coverity scan issues, which are pretty trivial; these are separated into commit https://github.com/srowen/spark/commit/1deecd8d9ca986d8adb1a42d315890ce5349d29c )

## How was this patch tested?

Jenkins tests

Author: Sean Owen <sowen@cloudera.com>

Closes #11657 from srowen/SPARK-13823.

1 files changed, 3 insertions, 1 deletions

diff --git a/external/flume-sink/src/test/scala/org/apache/spark/streaming/flume/sink/SparkSinkSuite.scala b/external/flume-sink/src/test/scala/org/apache/spark/streaming/flume/sink/SparkSinkSuite.scala
index 7f6cecf9cd..e8ca1e7163 100644
--- a/external/flume-sink/src/test/scala/org/apache/spark/streaming/flume/sink/SparkSinkSuite.scala
+++ b/external/flume-sink/src/test/scala/org/apache/spark/streaming/flume/sink/SparkSinkSuite.scala
@@ -17,6 +17,7 @@
 package org.apache.spark.streaming.flume.sink
 
 import java.net.InetSocketAddress
+import java.nio.charset.StandardCharsets
 import java.util.concurrent.{CountDownLatch, Executors, TimeUnit}
 import java.util.concurrent.atomic.AtomicInteger
 
@@ -184,7 +185,8 @@ class SparkSinkSuite extends FunSuite {
   private def putEvents(ch: MemoryChannel, count: Int): Unit = {
     val tx = ch.getTransaction
     tx.begin()
-    (1 to count).foreach(x => ch.put(EventBuilder.withBody(x.toString.getBytes)))
+    (1 to count).foreach(x =>
+      ch.put(EventBuilder.withBody(x.toString.getBytes(StandardCharsets.UTF_8))))
     tx.commit()
     tx.close()
   }